Plating of wire



Sept. 14, 1937. 'E'. c. DQMM PLATING OF WIRE N I w INVENTOR. 16m CAPLsTo/v Dom/w" Filed Dec. 19, 1935 ATTORNEYJ- Patented Sept. i4, 193? PLATING F WIRE Elgin Carleton Domm,

National Standard Company,

Niles, MichL, assignor' to Niles, Mich a corporation of Michigan Application December 19, 1935, Serial No. 55,202

2 Claims. (Cl. 91-682) shown housed in a hood l4, whence they pass over i This invention relates to the plating of wire, and is illustrated as carried out in plating a steel wire with zinc and then electrolytically depositing an outer coating of copper thereon.

In one-desirable arrangement of the novel apparatus ,used, the wire (after suitable cleaning) is passed into a bath of molten zinc (or other metal to be plated thereon) ,where it remains long enough not only to receive a coating of zine gal- 0 vanized thereon but also to have its temperature raised to that of the zinc bath (e. g. about 840 F.)

Preferably the wire, after leaving this bath is quenched, by passing over a wet roller or the like, to solidify and set the zinc coating without, however, substantially lowering theftemperature of the wire.

As quickly as possible thereafter, and stillat 9.

- temperature greatly in excess of the temperature of boiling waterie. g. at around 650 or 700 F.), passes directly into a hot aqueous electrolytic plating solution, preferably of copper cyanide.- The hot plating solution is acted on by the wire at its'still higher temperature, so that it has an immediate effect as soon as the wire enters the bath of cleaning the zinc surface and starting the 25 deposition of the copper on the zinc under the .most favorable conditions, so that an extremely adherent coating is produced which, during storage after the plating is completed, is gradually absorbed by the zinc to form a thin coating of brass to which rubber can successfullyand firmly be vulcanized.

The plating apparatusis of novel construction and arrangement designed to secure continuous eirective circulation of fresh solution about the 3 wire being plated. This construction, and the novel composition of the solution and effective desirable current strength, and other novel and desirable features, will be apparent from the following description of the plating of a series of wires in the novel apparatus illustrated in the accompanying drawing, in which:

Figure 1 is a top plan view of the apparatus;

Figure 2 is a section through the zinc plating tank, on the line 2-2 of Figure l;

Figure 3 is a transverse section through the copper plating apparatus on the line 3-3 of Figure 1; and

Figure 4 is a longitudinal section through the 0 copper plating apparatus, on the line t-l of Figure l.

In the apparatus illustrated, a series (e. g. ten) of steel wires [0 are drawn from swlfts or the like l2, supported in any desired manner, through 55 suitable cleaning, washing, and drying means a guide roller it into a bath covered by insulating material 22 such as--ex 18 of molten fzinc 20 pended mica (known commercially as Zonovherein is capable of utilization with the various metals and plating-bath formulas described in those patents; for most purposes, however, I prefer to galvanize on the wires a plating of zinc and then apply tothe zinc-plated wires an electrolytically deposited coating of copper.

The wires remain in the zinc bath long enough not only to receive their zinc coatings but also to be raised substantially to the temperature of the forced into the zinc by any molten zinc, or at least near enough thereto to I pass as described below into the copper cyanide or equivalent solution at the desired high temperature.

Preferably, as the wires leave the zinc bath,

the zinc coatings are set and solidified (without substantially lowering the temperature of the Wine) by passing them over a quenching roller 28 having its bottom immersed in water in a trough 30.

In order to make the apparatus as compact as possible, I prefer to arrange the copper plating apparatus described below beside the abovedescribe zinc-plating apparatus, leading the wires thereto around two right-angle bends formed by series of guide rollers (not specifically illustrated) arranged at 32 and 34.

The copper plating, or equivalent electrolytic plating, apparatus illustrated is of novel form and arrangement designed to insure a continuous supply of fresh plating solution to the wires being plated. The apparatus may include a relatively long lower bath or tank'36, containing a supply of an aqueous solution of copper cyanide containing, for example, about to 35 grams of copper and 20 to 24 grams of cyanide per liter. I find that this solution operates best at a temperature of about 160 F. As explained below, part of the necessary heat is derived from the hot wires 10.

, The solution is continuously fed from the lower tank 36, by means such as one or more pumps 38 shown as driven by motors 40, to the centers v end in a series above the solution in the tank 36.

The solution in the tanks 42 flows both ways along the wires III, and overflows back to the lower tank 36 through notches 44 in the ends of the tanks 42. The wires III are arranged in the notches 44.

The plating current passes (preferably at about 30 to- 40 amperes per square foot of surface of the wires immersed in the plating solution) to the negative connection to rolls engaging and pressing down on the.wires l0, supported by pairs or idler rollers 52 on opposite'sides of the rolls 50, a series of mils Ell-J2 so connected being arranged at'each end 01 each of the upper tanks 42. The bottom or each roll 50 is slightly below the tops 01' the corresponding rolls 52, to insure good contact with the wires.

The positive current connection 54 is connected in the usual manner to copper plate electrodes 56 immersed in the solution in the upper tanks 42. These connections may have their resistances s0-balanced that substantially equal currents flow between the wires and the respective plates. 4

The hot wires, at approximately a temperature oi around 650 to 700 F., i. e. greatly above the temperature of boiling water, thus pass directly into the plating solution in the first tank, the hot wires causing a very active reaction or the solution which clears of! any traces of zinc oxide or other impurities immediately, and starts a very active deposition of the copper on the clean zinc surface, so that the copper is in such intimate contact with the zinc as readily to alloy therewith on standing, as explained in my above-identified patents, to form the desired brass surface.

The plated wires pass through suitable washing and drying means in a hood 60, and over suitable devices 62 (illustrated diagrammatically as driven by motors 64) to wind them on switts or. the like 68.

, The above-described process is also applicable to the electro-plating oi zinc on a hot-galvanized wire from a bath oi zinc cyanide, and to plating with other metals from an alkaline solution.

While one particular arrangement of the apparatus has been described in detail, it is not my intention to limit the scope of the invention by that description, or otherwise than by the appended claims.

I claim:

i. That method of plating a steel wire which comprises passing the wire through molten zinc to receive a zinc coating and at the same time be raised to a relatively high temperature, quenching the zinc coating without greatly lowering the temperature of the wire, passing the highly heat-v ed zinc-plated wire directly thereafter through a hot aqueous copper cyanide bath, and passing a current through the bath to the wire immersed therein, whereby the highly-heated wire as it .enters the bath is cleared of impurities and is then plated with copper.

2. That method of plating a wire which oomprises passing the wire through a molten metal to receive a metallic coating and at the same time be raised to a relatively high temperature, quenching the coating without greatly lowering the temperature of the wire, passing the highly heated plated wire directly thereafter through a hot aqueous metal-salt bath,and passing a current through they bath to the wire immersed therein, whereby the highly-heated wire asit enters the bath is cleared of impurities and is then plated with a second metal.

mam ICARLETON 003m. 

